Yeon, Jaeheum (2017-05). Rapid Concrete Pavement Spall Repair Using 3D Scanning and 3D Printing Technologies. Doctoral Dissertation. Thesis uri icon

abstract

  • Conventional methods for repairing damages to concrete pavement require a certain amount of time, regardless of the scale of the harm. The area must first be cleaned; this means that the damaged section must be separated from the surrounding area by sawing around its edges. The failing concrete is then broken up and removed. After pouring fresh concrete into the resulting hole, the U.S. Department of Transportation recommends waiting at least seven days before proceeding to the next step. Vehicles must be detoured for the entirety of this period, which often results in vehicle depreciation by as much as $140,000 per a repair project. Considering the indirect losses that can be caused by this process, stakeholders often find it difficult to decide when palm-size spall damage should be repaired. Many government agencies wait until the damaged sections become severe enough to justify a road closure. This dissertation presents a novel idea for speeding up the repair process for palm-size spall damage of concrete pavement: the use of 3D scanning and 3D printing. This study presents the suggested method to repair small damage on a concrete pavement using a prefabricated concrete segment tailored for the damaged area. The suggested method begins with scanning the damaged area using photogrammetry to get a 3D model. After that, printing out the obtained 3D model using a 3D printer. The output of a 3D printer is used as a formwork. And then pouring concrete in the formwork and curing a concrete segment tailored for the damaged area. Last, plug a pre-fabricated concrete segment in the damaged area after the adhesive is applied. However, each step of this spall repair sequence has its tolerance such as the level of the accuracy of the 3D scanner and the shrinkage of the output of the 3D printer. When these errors are accumulated, we can simply assume that there will be a certain space between the bottom of the prefabricated concrete segment and the surface of the spall when the concrete segment is later inserted into the spall. This space will be filled with an adhesive. But it is not known yet to what extent the adhesive layer will be formed. However, it can be predicted that the thickness of the adhesive layer will have some effect on how it will hold the concrete segment. Therefore, this study identifies the maximum shear stress and proposes a modified slant shear test method to experimentally investigate the influence of bond line thickness of epoxy-resin adhesive on shear strength when the glue applied to a concrete adherend. Also, this research investigates the attached concrete segment is strong enough to handle the maximum applied stress. The conclusions of this research are that first, it was found that having an adhesive layer between a concrete segment and a spall has better adhesive strength than a perfect fit between a concrete segment and a spall. Also, it was found that the spall repair method using 3D printer is sufficiently realistic. Last, the ultimate shear strength of three epoxy-resin adhesives that were used in this study can be predicted when the measured bond line thickness applied to the variable of the determined mathematical relationships of each adhesive.
  • Conventional methods for repairing damages to concrete pavement require a certain amount of time, regardless of the scale of the harm. The area must first be cleaned; this means that the damaged section must be separated from the surrounding area by sawing around its edges. The failing concrete is then broken up and removed. After pouring fresh concrete into the resulting hole, the U.S. Department of Transportation recommends waiting at least seven days before proceeding to the next step. Vehicles must be detoured for the entirety of this period, which often results in vehicle depreciation by as much as $140,000 per a repair project. Considering the indirect losses that can be caused by this process, stakeholders often find it difficult to decide when palm-size spall damage should be repaired. Many government agencies wait until the damaged sections become severe enough to justify a road closure.

    This dissertation presents a novel idea for speeding up the repair process for palm-size spall damage of concrete pavement: the use of 3D scanning and 3D printing. This study presents the suggested method to repair small damage on a concrete pavement using a prefabricated concrete segment tailored for the damaged area. The suggested method begins with scanning the damaged area using photogrammetry to get a 3D model. After that, printing out the obtained 3D model using a 3D printer. The output of a 3D printer is used as a formwork. And then pouring concrete in the formwork and curing a concrete segment tailored for the damaged area. Last, plug a pre-fabricated concrete segment in the damaged area after the adhesive is applied.

    However, each step of this spall repair sequence has its tolerance such as the level of the accuracy of the 3D scanner and the shrinkage of the output of the 3D printer. When these errors are accumulated, we can simply assume that there will be a certain space between the bottom of the prefabricated concrete segment and the surface of the spall when the concrete segment is later inserted into the spall. This space will be filled with an adhesive. But it is not known yet to what extent the adhesive layer will be formed. However, it can be predicted that the thickness of the adhesive layer will have some effect on how it will hold the concrete segment. Therefore, this study identifies the maximum shear stress and proposes a modified slant shear test method to experimentally investigate the influence of bond line thickness of epoxy-resin adhesive on shear strength when the glue applied to a concrete adherend. Also, this research investigates the attached concrete segment is strong enough to handle the maximum applied stress.

    The conclusions of this research are that first, it was found that having an adhesive layer between a concrete segment and a spall has better adhesive strength than a perfect fit between a concrete segment and a spall. Also, it was found that the spall repair method using 3D printer is sufficiently realistic. Last, the ultimate shear strength of three epoxy-resin adhesives that were used in this study can be predicted when the measured bond line thickness applied to the variable of the determined mathematical relationships of each adhesive.

publication date

  • May 2017